The invention relates to a turbine engine guide vane, to an annular set of turbine engine guide vanes, and to a turbine engine including such a set of guide vanes.
A bypass turbine engine 1 for propelling an aircraft is shown in FIG. 1, in section in a vertical plane containing its main axis A. The turbine engine comprises an outer casing 10 containing, from upstream to downstream in the air flow direction: a fan 12; a low pressure compressor 14; a high pressure compressor 16; a combustion chamber 18; a high pressure turbine 20; a low pressure turbine 22; and an exhaust cone 24.
An inner casing 28 is arranged inside the outer casing 10 around the compressors 14 and 16 around the combustion chamber 18, and around the turbines 20 and 22. An annular set 30 of outlet guide vanes extends downstream from the fan 12 between the casings 28 and 10, specifically being located in the region of the compressors 14 and 16.
In operation, the inner casing 28 splits the stream of air accelerated by the fan 12 into a primary stream Fp that feeds the compressors 14 and 16 and a secondary stream Fs that flows between the casings 28 and 10 and that is therefore ejected from the engine after passing through the set 30 of outlet guide vanes in order to supply a portion of its thrust.
The outlet guide vanes (OGVs) comprise a plurality of vanes arranged in an annulus around a ring 32 carried by the inner casing 28. The guide vanes serve to straighten out the flow of air leaving the fan.
For better efficiency of the outlet guide vanes, they need to have good aerodynamic performance, and in particular they need to limit losses on passing through the annulus they form.
Furthermore, under the effect of the air stream, the guide vanes are subjected to high levels of stress, thereby leading in particular to phenomena of the vanes twisting and bending. A vane twisting suffers deformation around its own stacking axis. A vane bending suffers deformation about the tangential axis that is tangential to the rotation of the fan, and thus to the ring 32.
These twisting and bending phenomena are analyzed by the twist bend coupling (TBC) parameter. The TBC parameter at a point of a vane is the ratio between the amplitude of twisting and the amplitude of bending at that point. The TBC parameter of outlet guide vanes reveals their tendency to float in operation. It must be acceptable from the point of view of operability of the turbine engine and from the point of view of its aerodynamic behavior.
It is therefore important to ensure that the increasing efficiency in aerodynamic performance does not degrade the TBC parameter relative to a target TBC parameter, as determined during a stage of calculating the dimensions of the turbine engine.